Thickened lubricants



Patented Oct. 13, 1953 UNITED STATES PATENT OFFICE 2,655,476 THICKENED LUBRICANTS Everett 0. Hughes, Shaker Heights, and Ernest (J. Milberger, Maple H eights, Ohio, assignors to The Standard Oil Company, Cleveland, Ohio,

a corporation of Ohio No Drawing. Application October 26, 1951, Serial No. 253,448

agent is an inorganic substance.

Mineral lubricating oils are the most common- 1y used lubricants. Although they are available in various viscosity grades, they all possess flow properties which do not adapt them for many lubricating needs Where a terial not compatible with the oil, such as silica. These aerogehthickened lubricants are far superior to the soap-base greases in stability at high temperatures as the following table shows:

, i TABLE I Soap or other thickener Appearance at 400 F.

Do. Hard-separatlor1 of soap.

olidifies hard mass. Soupy. Complete oil+soap. Unchanged except somewhat thinner. Unchanged, upon stirring, breaks down into a heavy liquid.

separation of lizers under all conditions of use, especially severe 1: they do not have an advantageous effect on high temperature stability, and may even reduce or even destroy the high temperature stability of aerogel greases.

' Appearance after cooling ni'trogem atoms and Accordingly, it is an object o! the present invention to provide an aerogel-thickened lubricant having improved stability against the deleterious action of water under extraordinary conditions of use.

object to provide an aerogel thickened lubricant having improved water-resistance and also improved stability at high temperature, the two properties in which such greases are noticeably deficient.

It is also an object to provide an additive capable of improving the water-resistance of aerogelthickened lubricants;

It is a further object to provide an additive which notionly isscapablelof improyingthewaterresistance}; buttis" also capable high temperature stability of aerogel thickened lubricants.

In accordance with this invention, it has been discovered that the water resistance orzalubricating oil thickened with a non-abrasive, inorganic thickening or gelling agent, and, particularly-finely-divided silica, a silica aerogelibeingjllustrative; can be improved by including in the composition a surface active, oil-dispersible, water-insoluble amino imidazoline of the generai structurer they can be substitutedina straight orbranched aliphatic. chain or in. a heterocyclic ring, which can. itself bear alkyl,,.alkylene, hydroxyalkyl, or hydroxyalkylene. groups, desirably in the l.-posinone-as in. the above imidazoline. ring, ..Thus R can-be a mono, di.- or tri-ethylene amino group, or at;i-alkyleneeimidazolina group,.. or a .l-ralk'ylene. amino imidazoline, group.

is an: alky l-,,.hydroxyalk l,. alkylene orlhy- 'droxyalkylene, group, :These compounds are prepared.byreaction or aliphatic acids andpolyaminesiollowedby cyiclir zationa in theriollow-ing way;

in which R has'two basic 20: carbon Amino imldazohnes from 4 tohabout off improving?- the;

atomssuch as di'et'hlene diamino-and triethylene trian'iino, and 'the-alkyl-substituted N-alkylwe and N--alkylene-am-ino imidazolines (wherein" R is attached to-= the i midazoline nucleus of the general formula through the N-alkylene or properties which does: not markedlyfiafiect .thickenedi'lubricanty. i.

" riallymodifiedi *imidenoline N- alkyleneamino group), are readily available and are preferred. The chain length for R dependent upon character of the group; the larger atoms, relative to the number of amino nitrogens, the more the group takes on the character of a hydrocarbon and loses its basic or amine character. An upper limit of about 5 carbon atoms per amino nitrogen is indicated by this requirement, with about a maximum of 30 carbon atoms for the B group.

R, which is acid, can have from 11 to 21carbon atoms, such as undecyl, tridecyl, abietyl, pentadecyl, undecenyl, heptadecyl, ricinoleyl, andrheptadecenylr The thickeneddubricant containing; these imidazolines has excellent temperature susceptibility are characteristic of the silica aerogel greases, and. in addition is highly resistantzto: deterioration by water.

the amino imidazoline also the consistency of the e., the amount of the inorgani'cglling, agent to impart a given consistency to the thickened lubricant is not mate- Furthermore the inclusion of the will not effect a change in the consistency. of the thickened lubricant upon storage. This is to be contrasted with other materialswhich, impart a lower initial consistency or a lowericonsistency on' standing,

"Due to the inorganic nature "of: the "gelling agent, ,the thickened'lubricanthas' excellent storage; stability. This is to be, contrasted withthe.

heat susceptibilityand detenorationof fatty ma- The presence, of

The preparation is simple andreadily: adaptable to continuous operation: a contrasted with, the involved grease-making techniques which are often considered the industry as an art.

The 'oilstock used in making the thickenedlubricant'may be widely varied as contrasted with present grease 'making requirements in which theoili. inmany cases is; critical to meet: certain specifications.

In addition, permits the supply, which which fats andsoapsare scarce and many times of pronounced non-uniformity;

The inorganic gelling agent to'be used in'making'the thickened lubricant in accordance with this invention may be any inorganic material which forms a gel: with a lubricating oil and which is so finely divided as-to be non-abrasive. The preferred materials are, may be formed from any material not incompatible with oil, such as silica, alumina, and other geli forming metal oxides.

A series of'silica aerogelswhich can be used as the inorganic'gellingagent of the invention are manufactured by Monsanto and marketed under the trade name Sa-ntocel.

Santocel-C is prepared from'a sodium silicate solution in" the-followingway: The solution is neutralized with sulfuricacid tostand-until the mixture sets to form ahyd-rcgel "The lay-product sodium washed out by the repeated washings with water. The continuous water phase in this hydrogel is then replaced" by continued washing with alcohol until an alcogel is formed. -In order 5 to remove the liquid-J phase without a. collapse of the gel structure;- the alcogel .is placed in an autoclave which .151 then: heatedi' above-the critical. temperature of the alcohol and the pressure is allowed to increase to a point above the critical pressure of the alcohol. The vent valve is thenopened and the alcohol allowed to escape. Under these conditions, the silica gel structure remains practically undisturbed and the liquid phase of the gel is replaced with air. The material. is then re duced in particle size by blowing it through a series of pipes containing sharp bends with jets of compressed air. agglomerate particle size of about 3 to 5 microns. Santocel A is prepared as set forth for Santocel. C up to the point of removal of the product from the autoclave. continuous heating chamber where it is locate for hour to a temperature of about 1500 F.

ARD is a modification of AR, diifering only in that ARD is densified by extracting air under vacuum, and therefore has a smaller volume nAR.

AX is an A which has not been devolatilized. CDv is a C which has been devolatilized as set forth. for Santocel A. The Santocel is reduction Density, grams per ml. AR 9.929 ARD 0.056 to 6.064 C 0.082,

In general, AR and ARD show superior gelling ability and the As in general are better than the than the underolatilized aercgels.

Other types of inorganic gelling agents which may be used include a Fumed Silica marketed by B. F. Goodrich Company. it is finely divided and appears very much. like an acrogel. .t i made by a combustion or vaporization process, as a source or" white carbon black for the rubber industry. The particles are several microns in size and porous in nature.

Another material is Linde Silica Flour" marketed by Linde Air Products Co. similar in physical appearance to the silica aero gel. The particle size of the silica is purported to be 9.01 to 8.65 micron and to be manufactured by burning silicon tetrachloride and collecting the combustion product on cool plates analogous to the production of carbon black. The particles are thought to be aggregates or clusters of particles rather than of sponge-like character.

In preparing thickened. lubricants it is necessary to remove the water from the sol and replace it with an oil. This is possible by formulating the lubricant and removing the water by ling agent and the oil will vary somewhat deinorganic, gelling agent falls within the range of 5 to 20%, and in most cases would fall within the range of '7 to 12%.

characteristics. The bleeding tendencies are decreased by increasing concentrations of the gelling agent.

The relative concentration of the gelling agent effects the most significant alteration, particularly is relatively ble amino imidazolines .candoe :employedtjn ac-:

cordance with thepinventionyjtoy improve the water-resistance and high temperature stability of :aerogel-base greases.

The: im'idazoline need not be oil-soluble; but itshould be oil-dispersible. .It should; have a minimum boilingpoint ofabout 150C. when its primary purpose .is to stabilize theigrease :at high temperatures, but 'the boiling point is :not material when only the water-stabilizing..propertiesiof the-imidazoline are tobe utilized.

l'Ihe-imidazoline isincorporated in the aerogelbasegrease in a concentration ranging-from 0.25 to about 1% by weight ofthe. aerogel-hase greaseygivessatisfactory results. 'Ihere isno reason to employ more imidazoline than is neces-;

sary .to achieve the desired efiect,'but excessive amounts do not harm, and amounts up. to 5% or even higher have been successfully "employed. -Ina some instances, the-composition containing the :amino imidazo'line stabilizer .may not display a .longlife,- whenxused .continuously ac high temperatures. A breakdownin high'temperature stability at high .temperatures'ifxit appears iswdue to a decomposition, through oxidation, or 1 theamino: imidazoline stabilizer of the in-' vention. t In such 1 circumstances, itais desirable to include in the composition an antioxidant for the amino imidazoline stabilizer. Conventional amine antioxidan which are more-readily oxidized than the amino imidazoline of the inventions can be cmployed-izfor 'thispurpose. Tetramethyldiamino diphenylmethane, available under-the trade name Galco MBfis a particularly desirable antioxidant forthe amino -imida zolines'of the invention. Only small quantities are required and ordinarily an amount ranging from Odie-about =1%'=by weight of the aerogel base-grease-is ample. There is-no reason to employ-more antioxidant than-is necessary to produce the desired'effect, but excessive-amounts do no' harm' and amou tsup to5%-- can-be used, if" desired.

The:compositionis made simply bymixing' the inorganic gelingagent, the "oil; the-amino imidazoline andthe antioxidant in any order or manner.

In, one embodiment, the amino imidazoline and, desirably, the "antioxidant, can -be incorporated with the inorganicge'lling agenteither by =mixing d'rrectly -or,-ifdesired; by dissolving them: in a volatile hydrocarbonsolvent,such as pentane, adding oil,- mixing"the solution with the-inorganic sell ng agent, and then evaporating" the solvent. 7

"Generally; =the---amino "imidazoline -and, optionaily,-antioxidant are dispersed in-the-oil and the inorganic; gelling agent added thereto and Example No.

mixedtherewith. Any simple mixing technique can be. employed and, if desired; the mixturescan be homogenized .n a colloid mill, although -this is not necessary.

The. composition. of the invention is not=limited to the oil; gelling .agen. and aminoimidazoline. Any ofthe-materials conventionally. addedito lubricants and greases can be included. .The expression :consisting essentially of as used herein is intended to refer to, the components which are essential. to the composition,..namely. the oil, theinorganic gelling agent and the amino imidazoline,:.and the expression does not-exclude other components from the composition which do not render it unsuitable for lubrication, such materials being, for. instance, the. antioxidant, high polymers to modify viscosity or viscosityindex, materials to'impart tackiness, lubricating solids such as graphite, antioxidant additives, corrosion inhibitorsofvarious types, sulfur, additives to render the lubricant suitable for use in gears, for cutting-grinding, etc.

The following examples illustrate preferred embodimentsof the invention:

Examples 1 to 18 Several amino imidazolines of the invention in a '0.8%- concentration were incorporated in a thickened-lubricant formed from.

The water-resistant aerogel base grease formula in Table II is as stated. the imidazoline being l-B-hydr'oxyethyl2=heptadecenyl imidazoline.

An isobutylene polymer sold by the Enjay Company Inc. and commonly used in compounding greases.

3 Tetramethyldiarninodiphenylmethane.

A FriedeLCrafts reaction product, useful as a pour point depressant and soldby the Enjay Company, Inc.

A rigorous test to determine water stability was carried out on samples of the thickened lubricants. In accordance with this test a 2 X 2 in. stainless steel plate was coated with a uniform layer of the thickened lubricant, following which the coated plate was immersed in a beaker filled With-tapwaterand boiled for a period of minutes. A grease made only from oil and silica aerogel, for example. (referred to in the table which follows as aerogel base grease) broke down immediately upon contact with the boiling water. The thickened lubricant which according to an empirical visual observation was essentially unchanged in appearance was rated very good or good. lithe grease separated (oil to surface, gel to bottom) it was rated bad or no water stability. If some'emulsification was noted, but the grease was not disintegrated, it was 'rated (lfairj? TABLE II Additive oil Additive structure Solubility Water Stabmty l Ae cc base grea s of he =--prior art: r 4

i r grease Melts, s Separation 2..Aerogelbas e grease" do.., Norm -3'. Water resistant-hero, mine 0: s l bl VGUOCL gchbase grease. 1-B:hydxoxethyld-heptadecenyl imidazohnc. .4. Armeen' 10-1) (Ar- Pr aryamme: 13ml :mour). i Om 3% C3 I 12 5. ,-Cetyldimethyl1amme:

TABLE II-Continued Example N o. Additive structure gqggm g Water stability Imidazolines which are not effective additives:

HlC- GH| Soluble.. Very poor. Emulsiflcation I l with water-sop. of oil and EN N San 0 (717 112 3 7 H1(I?--(!3H: .-do Very poon gslmglgifleatloln an se .0 01.2111 antoce. HN\ &N p

R is polypropylene 8 -do No v vater sta bility. Gompeese.o oil ndS HZCHCHI tocel. p a an -CH2N N l 0 1 JJHHM 9 H,ccm -do Do. OuHu-N N l t I 011E 10 HzIC---(|3 Not soluble Very p oor. Emulsifleatlon :11 W88! f 011 (1 EN N Santocel. 0 an C f JuHu u HICMCHI Partla1lyso1uble. Very poor. Emulsification I I wlth watersep. of oil and Santocel. HN\ N Tall oil H C Residue 1 12 HzC--lFH1 Soluble D HN\ N (bHa)1CH=CHCH1CHOH(CH2)5CH: Amino imidazollnes which are effective water stabilizers in accordance with the invention: 13 .l HER-ICE: do Verygood.

H:NCH:CH:[NHCH:CHz]z-N N 0 (B11311 14 HNI I I d0 Ggod. Surface whit r t ome sep. of oil and S t NHaCH:OH1N N cel sun greaselike. an

0 511 2: 15 H:('J H: do Verygood. HzNOHgOHzNHGHgCHz-N N C 2:11!" 16 HzC -CH: do Do.

H :N CH: CHIINH CHzCHaIr-N N 1 Additive oll Example No. Additive structure solubility 7 Water stability 17 v H2 C--(EH1 Slightly soluble.-. Very good;

mNomomtNHomoHgrN N (.7 Tall oil HCresidue" 1s reckon: ree m1 so1ob1e;-;=.-;-.-.--.. Do. N N-oH,-HrN N C C 01111:: 41:31 19 Hz(%- (EHz Hie-QB! .1 d0 D0 N NH4Ca-NHCaHi-N N /l r E V Gul s: 7 (31 15 HaC fiJH: HaC--CHz do Do. N N lor-NHc,nl-N N (1 C CH: (Err- 2: 21 Hiecm mo ora do Do. N N-CHzC'Eh-N N 0 r 11 2: OH: 7 22 e,o -crr1 Hie on, ....-do... Do. N N-CH2CHr-N N 1 $11K CH: 7 23 HzC,- '--'C 2, HzCF- Notsoluble Fair. Some emulsification l r l and sepuofSantocel. St N i NCH1CH N N agrease;

1 f CuHu 015 31 24 HlC-(l3H1 Notte'r'yioodfln Very good.

mNomomN oHlcm-m N l Derived by reaction of tall oil fatty acids with the corresponding diamine, as set forth in the reaction in column 3.

A comparison 0 hility test (Table ample l3, andE the importance the imidazoline Imidazolines lac tive, while imi very efiective of Example 14 with Example' l basic nitrogen are better than on The determ bility was mad of grease in a ing them in a ted of a solid a1 electrical heaters." Six' holes, ni'risions are compared in Table lfwith'those'of the standard AS'lZ'M cone, ASTM designation beaker, were drilled into the top of the block, to- 21v-4s,"'aesenbea' "on page 143 of the Novemgether with a thermocouple, so that a measure ber 1948 edition of D-2 Specifications for Petroof the temperature of the block could be obtained. 5". leum Products. The cone and grease cup emfurnace consis heated by intern each large enou gh to accommodate a 150 cc.

f the results of the water sta Inthis manner, six beaker's'co'uld behe'ated'sl- II) for Example 10 with'Exmu1taneously'.-The' beakers'containing the grease xample 11 with Example 1'7,shows were placed in the aluminum furnace and held of the l-amino group in making there until the equilibrium temperature of the and effective water stabilizer. grease was 400 F. The samples were stirred at king anamino group are ineffecfive min'ute intervals during heatinge Aiter th-i's dazolines bearing such a group are the grease: was'allotved to cool to room temperastabilizers. Further, a comparison ture overnight and then was stirred vigorously 5, shows that; two with a spatula. Micropenetration measurements e I were obtained on the grease before and after the ination of high temperature Star 5---test; procedure, and the results are expressed in e by placing approximately cc. the table below as. per cent increase in penetraml. beakeri The beakers were tid'n.

heated to the test temperature (400 F.) by plac- The micropenetration technique employed ren aluminum block furnace. Thls quired a very small sample of grease. The mlblock of aluminum 70, crocone employed was specially built, and its diployed in obtaining the following test results re- 14 for any 01' the imldazolines in the greases of the quired a minimum sample size of 35 ml.

preceding examples with good results: TABLE III MICROOONE DIMENSIONS Additive structure Hfl-F EJH: NH1CH:CH:(NHCH:CH:)-N N N C D' t nifiiitfitun Errata? E151. NHPCHI H=C-H, Volume. cc I I gone glanllfilcup Slrfiiifi CHN\ 4N one mg .011 op t. of assembly? gms NH1-OH| O t. of assemblyYsq. surface 11B." EEC-CH:

1 Calculated.

NHeCHzCHNFH-IL' 1 1' The following results were obtained on the NH: 0 aerogel base greases of Examples 1 to 18: g

H 0x03 TABLE IV 25 2 I NmomcmNomcm-N N 1% HI C Block performances (g N 12H" Orig. 1 Hflf C'H,

NH,cH,oH.oHcH, N 11: 68 y 3'; NH) C 100 37 ltHai a: 3; NHzCHzCH-CH-N N 0: mar 01 cncnovcn momma: l-nozachhxam cbwmw vhOmwm H 91 g nHas 14 EMF-CH1 Baa-CH2 15 87 N mwmcmmzcmom-N N 16 17 11 134 (B J} 78 11s 19 so 110 g g; I mc cm 20 \N OHaCHzNHOHiOH:-N N 21 66 88 C 22 72 94 n "H2: 23 s2 24 95 135 NHzCHgCHzNHCHzOHaCHOHr-N N The importance of an (511m, :1 nta 1r gards bocth h m 18 Hie-0H, I MI ersaliyisevle p No 10 has a hydroge -position, and Ex- E K 2? ample No. 13 is similar to No. 10 but has a trl- 0 NH, 0 ethylene triamino group in the 1-position, and cum, (5, is much superior to No. 10. A comparison of Ex- 35 ample 13 with Nos 15 and 16 shows the group in N T he 2-pos1t1on should have more than 11 carbon HZCMCHQ atoms for best high temperature stability. Ex- JL I l; amples Nos 11 and 17 are an additional com- N parable pair, showing the critical nature of the I l-amino group It W111 be noted that Examples "H35 13, 1'7, 20, 21 and 22 are all superior to the aerogel NHPCH, H2O CHI base grease in high temperature stability, while CH CH I I retaining excellent water stability. 2

NHr-CH: 0 Examples 25 to 37 (Sum.

The following imidazolines can be substituted 7 In the examples, the highetemperature stability of the aerogel greases i's tested by heating'the much as the ahighest wtemperature to which a grease is subjected under even extraordinary conditions of use is about 300 F., but it was adopted as a suitable test standard by which-to measure the high temperature stability :of the greases because a grease stable at 400 F. will definitely have the stability necessary to withstand heatingto 300 F. It will be understood that iorrnormalpurposes an aerogel grease. need not be stable attemperaturesabove about 300 F., and thatmany of the greases of the invention at least meet this requiremen Where the term high temperature stability is used, it will be understoodto mean that the aerogel grease {is stable at at least 300, F.

While the'invention is'not to be limited to any theory-or explanation, it may be of assistance in understanding the effect of the imidazoline on the water-resistance of the grease to explain that the inorganic gelling agent is either oil-wettable or water-wettable, but is-preferentially :waterwettable and has a .great compatibility with water. When a lubricant thickened with an aerogel, for example, is contacted with water, the water replaces the oil in the geland thenseparates fromthe .oil. ,Inraccordancewith the invention; the imidazoline, due to" its-surface activity, becomes attached to the silica and protects it from being wet by the water.

The imidazoline nucleus, since it possesses cationic character, is attracted to the anionic silica particles, withthe resultathat the hydrophobictalkyl group of the molecule projects outward. Since water molecules are thus prevented from contacting the silica, he stabilizing; agent, although, less polar than water, is not :eluted. However, :the coated silica particles are easily wetted by oil since the long chain alkyl groups are oleophilic. thickened lubricant which permits the imidazo- ,lineito come into contact with. the inorganic gelling agentso asito protect, it in this way, may be-employed.

This application is a continuation-in-part of cur -application Serial No. 240,452, led August 4, 1951 which is a continuation-in-part of: application Serial No.- l19,752,filed October 5, 1949, now abandoned.

We claim:

1. A water-resistant thickened lubricant of good temperature susceptibility properties consisting essentially of a mineral vlubricating oilof lubricating viscosity as the major component, an:

inorganic water-sensitive gelling agent imparting a grease-like consistencyvtoi the oil upon addition thereto as .aminor component, and an oil-soluble, water-insoluble, surface-active polyamino imidazoline being in an amount less than the Any mode of compounding the.

greases to 400 F; "This is an extreme test, mascordance with.

'-all;yl,-- alkylene, hydroxyalkyl and hydroxyalkylgellin -re ent rand zlnipartingu-stabil ty a ainst deteriorationibyfwater,andhaving-;the,fcr;nula..

H,o- 1H, a -N n where R is a radical containing an amino group andRfisiselected'from the group consisting of alkylyalkylene, hydroxyalkyl and hydroxyalkylene groups.

2., A water-resistant thickened lubricant ot .:.good temperature susceptibility properties-intac- -cordance with claim 1, wherein R is diethylene amino sl-A water-resistant thickened =l-ubricant 10f good temperature susceptibility rqperties inaccordance-withclaim '1,"Wh818'ln"R'1S- triethylene amino.

4. A water-resistant thickened lubricant of good temperature susceptibility properties in accordance with claim '1,- wherein-R is-an alkylene imidazoline group.

5. A water-resistant thickened lubricant of good temperature susceptibility properties in accordance with claim 4, .wherein R iisuan ethylene imidazoline group.

6. A iwaterrresistant thickened "lubricant-10f good temperature susceptibility properties in acclaim A, wherein iR'epis ard q'illil eneamino imiidazoline gr. up

0 '7; A water-resistant thickened ilubricant'or good temperature susceptibility; properties. in .ac-

cordance-with,iclaim l, wherein R' is ricinoleyl. 8. A water-resistant :thickened lubricant of goodtemperature susceptibility properties =-in -accordance--withclaim l, whereinaR is.heptaidecyl. V

9.,A water-resistant lthickened jlubricant of good temperature susceptibility; properties in accordance with claim L wherein R- is-heptat decenyl.

10. ,A i watereresistant wthickened lubricant of good temperature susceptibility properties in accordancewith claim- 1, "wherein: R is=,-;un';decy1.

A zcornpositiontiori imparting a: rease-like ,consistencyuto ,avminerallubricatingpil; ,oi lubricating viscosity, and also -j-i-mparting gstability against 1 deterioration byv vwater, ;comprising an inorganic: wwater-sensitive; gelling, agent and ;,an

,oil-soluble, mater-insoluble, surface :active poly- ,amino imidazoline 1 having :the; formula.

mo e Hi R-N N where 1 R -is' a radical containing-ian amino1 group and R" -is-selected from the group: consisting of em groups said compound bei-ng -inan amount 'l2.;A =-water-resistant thicleened lubricant not good temperature susceptibility properties-inac- -cordance--with=claim I l, wherein the imidaz'oline Hi0" CH1 E 13i-'-A water-resistant thickened" lubricant oi 17 good temperature susceptibility properties in accordance with claim 11, wherein the imidazoline is:

Hie-H2 uHza 14. A water-resistant thickened lubricant of good temperature susceptibility properties in accordance with claim 11, wherein the imidazoline is:

HzC CH:

4311112: 15. A water-resistant thickened lubricant of good temperature susceptibility properties in accordance with claim 11, wherein the imidazoline is:

16. A water-resistant thickened lubricant of good temperature susceptibility properties in ac- HnC OHa 6H. time where R is a radical containing an amino group and aving from 4 to about 20 carbon atoms and R is selected from the group consisting of alkyl, alkylene, hydroxyalkyl and hydroxyalkylene groups having from about 11 to about 21 carbon atoms.

EVERETT C. HUGHES. ERNEST C. MILBERGER.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Jordan Nov. 28, 1950 Stross May 22, 1951 Number 

1. A WATER-RESISTANT THICKENED LUBRICANT OF GOOD TEMPERATURE SUSCEPTIBILITY PROPERTIES CONSISTING ESSENTIALLY OF A MINERAL LUBRICATING OIL OF LUBRICATING VISCOSITY AS THE MAJOR COMPONENT, AN INORGANIC WATER-SENSITIVE GELLING AGENT IMPARTING A GREASE-LIKE CONSISTENCY TO THE OIL UPON ADDITION THRETO AS A MINOR COMPONENT, AND AN OIL-SOLUBLE, WATER-INSOLUBLE, SURFACE-ACTIVE POLYAMINO IMIDAZOLINE BEING IN AN AMOUNT LESS THAN THE GELLING AGENT AND IMPARTING STABILITY AGANST DETERIORATION BY WATER, AND HAVING THE FORMULA 